This invention relates to methods and apparatuses for fastening circuit boards to computer chassis.
Computers typically include a chassis that houses semiconductor devices, such as memory chips, processors, and linking circuitry mounted to a printed circuit board. The printed circuit board is typically attached with threaded fasteners to stand-offs, which are then attached to a surface on the chassis, also with threaded fasteners. Accordingly, the stand-offs secure the circuit board to the chassis while leaving a gap between the surface of the circuit board and the surface of the chassis. The gap is typically sized to prevent devices and connecting circuitry mounted on the circuit board from contacting the chassis, which could cause the devices to short-circuit.
One problem with the above design is that it can be time consuming to first threadably attach the stand-offs to each circuit board and then threadably attach each stand-off to the chassis. One approach to address this problem is to attach the circuit board to a plurality of rails with unthreaded fasteners and then attach the rails to the chassis, also with unthreaded fasteners. One such arrangement is an NLX circuit board available from Intel Corp. of Santa Clara, Calif.
The NLX circuit boards, however can also have certain drawbacks. For example, it may be difficult and/or intimidating for end users of the computer to remove the circuit board for service or replacement because tools may be required to remove/fasten the circuit board to the rails and remove/fasten the rails to the chassis. Furthermore, the rails are configured to attach only one type of circuit board to the chassis, and accordingly different rails are required to attach different circuit boards to the chassis. Still further, the circuit board must be properly grounded to the chassis to ensure that the devices on the circuit board share the same ground potential. Accordingly, the fasteners connecting the rails to the chassis and the fasteners connecting the circuit board to the rails are generally conductive to provide a conductive link between the circuit board and the chassis. This feature can increase the cost and/or complexity of the fasteners, and therefore increase the cost of the computer with conventional NLX board configurations.
The present invention is directed toward methods and apparatuses for removably securing printed circuit boards to a computer chassis. In one aspect of the invention, the apparatus can include a bracket for supporting a first computer circuit board or a second computer circuit board relative to the computer chassis. The bracket can include a bracket body having a first arrangement of bracket fastening sites aligned with attachment sites of the first computer circuit board, and a second arrangement of bracket fastening sites aligned with the attachment sites of the second computer circuit board. The apparatus can further include at least one circuit board fastener having a bracket coupling portion coupleable to one of the bracket fastening sites and a board coupling portion aligned with and configured to couple to one of the attachment sites of the first circuit board when the circuit board fastener is coupled to a bracket fastening site of the first arrangement. The board coupling portion is aligned with and configured to couple to an attachment site of the second circuit board when the circuit board fastener is coupled to a bracket fastening site of the second arrangement. The apparatus still further includes at least one chassis fastener coupled to the bracket body and positioned to couple to a corresponding fastening site of the computer chassis to support the bracket body and either the first or the second circuit board relative to the chassis.
In one particular aspect of the invention, the circuit board fasteners are unthreaded and can include first flexible prongs configured to removably engage the circuit board without the use of tools, and second flexible prongs configured to removably engage the chassis without the use of tools. The apparatus can still further include an electrically conductive gasket coupled between the attachment bracket and the chassis to provide the sole electrical path between the chassis and a grounding terminal of a circuit element on the circuit board.
The present invention is also directed toward a method for coupling a computer circuit board to a computer chassis. The method can include coupling the computer circuit board to a support bracket by attaching the computer circuit board, without threaded fasteners, to a plurality of unthreaded bracket fastening sites positioned on first and second transverse support members of the support bracket. The method can further include coupling the support bracket to the computer chassis by attaching the support bracket to at least one unthreaded fastening site of the chassis, also without threaded fasteners. The method can still further include grounding the circuit board by clamping a compressible conductive gasket between the chassis and a mounting plate of the circuit board.